Modern high definition TVs present video using High Definition Multimedia interface (HDMI). HDMI entails use of various additional protocols including High Definition Content Protection (HDCP), which ensures that only authorized displays such as authorized TVs can play HDMI from authorized sources such as authorized set top boxes (STB) and authorized disk players. The main video data is carried in one-way HDMI form and consists of three data channels plus one clock channel, typically conveyed using a signaling protocol known as Transition Minimized Differential Signaling (TMDS).
In HDMI, the device such as a disk player that sends multimedia to a display such as a TV is called the “source”, while the displaying device (e.g., the TV) is referred to as the “sink”. Accordingly, these terms may be used herein although without intending to be delimiting on the scope of the invention.
In addition, also typically housed within a single HDMI cable is a two-way Display Data Channel (DDC) line, for exchanging signaling such as periodic HDCP authentication and display capabilities known as extended display identification data (EDID). A consumer electronic control (CEC) line may also be provided in a HDMI cable assembly to carry consumer-generated commands. The various lines in the HDMI cable assembly may terminate in respective buses at the display (sink), e.g., the HDMI data terminate in a main HDMI bus and the DDC line terminates in an inter integrated circuit (“I2C” or “IIC”) bus.
As understood herein, if a poor quality or non-compliant transmission component is used, such as a HDMI cable assembly that is excessively long or of poor quality construction, DDC and/or TMDS data may arrive at the sink with marginal signal integrity, adversely affecting video/audio presentation.